Electrophotographic copying apparatus



Nov. 6, 1962 R, MAYO 3,062,094

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 4Sheets-Sheet 2 INVENTOR.

Clyde R. Mayo ATTORNEY NOV- 6, 1962 c. R. MAYO 3,062,094

ELECTROPI-IOTOGRAPHIC COPYING APPARATUS Original Filed Feb. 7, 1955 4Sheets-Sheet 3 F /G 5 30d INVENTOR.

Clyde R. Mayo A TTOQNE Y Nov. 6, 1962 c. R. MAYO 3,062,094

ELECTROPHOTOGRAPHIC COPYING APPARATUS Original Filed Feb. '7, 1955 4Sheets-Sheet 4 o V, WR. mm/A wm/ m .w \.4 L 2 0a m.. 90o. 6 1 m. 2-| vE-i flu F ESS.

United States atet 3,062,094 ELECTRPHOTOGRAPHIC CUPYING APPARATUS ClydeR. Mayo, Rochester, N.Y., assignor to Xerox Corporation, a corporationof New York Continuation of application Ser. No. 486,513, Feb. 7, 1955.This application Dec. 29, 1958, Ser. No. 783,388 18 Claims. (Cl. 88--24)This invention relates in general to Xerography and, in particular, toapparatus and mechanism for implementing the xerographic progress andfor projecting an original to a moving surface such as a rotatingcylinder or a moving plate. This application is a continuation ofcopending Mayo application Serial No. 486,513, led February 7, 1955, nowabandoned.

In Carlson Patents 2,297,691 and 2,357,809 there is disclosed anelectrophotographic process, since known as xerography, and apparatusand mechanism for this proc- The apparatus and machines heretoforedeveloped in accordance with the Carlson invention have been manual inoperation and relatively time-consuming. Accordingly, it is an object ofthis invention to provide a xerographic machine or apparatus capable ofoperating to produce a completed xerographic print in a matter ofseconds after original exposure and to repeat the process steps so thata further Xerographic copy can be reproduced immediately thereafter witha total cycle time in the order of fractions of a minute.

lt is a further object of this invention to provide that the exposure ofan original to be copied be made to a sensitive moving surface, whethera rotating cylinder or a moving plate, wherein the original to be copiedis positioned above a lens system arranged to iix an image of theoriginal on to the moving sensitive surface which in turn is spacedapart from the lens, and where proper registration of the image of theoriginal is made upon the moving surface by having the lens move inrelation to the original.

It -is a further object of the invention to provide a xerographicmachine capable of operating to reproduce a copy from an originalselectively, either one copy of the original or a plurality of copies ofthe orignal and to form such copies repetitively in quick succession.

It is still another object of the invention to provide a xerographicmachine comprising a rotating cylinder having at least a portion of itsurface electrophotographically sensitive, such cylinder rotatingthrough a charging station, an exposure station, a developing station, apaper feed and transfer station, and, if desired, a cleaning station anda regenerating station whereby a xerographic image is produced by thesuccessive steps of exposure, development, and transfer. It is a furtherobject of this invention to provide for the use of this machine inconnection with slit projection and in such case to arrange for suitableand even lighting and also to provide for the motion of the lens andother parts in a way to avoid vibration thereof.

Another object of the invention is to provide apparatus and mechanismfor reproducing automatically a representation of a visible image fromthe face of a cathode ray tu'be.

Additional objects of the invention will be understood from thefollowing specification and from the drawings in which:

FIGURE l lis a front elevation of a xero-graphic machine according to anembodiment of the invention;

FIGURE 2 is a rear elevation, partly in section, of a machine shown inFIGURE l;

FIGURE 3 is a rear elevation, partly in section, illustrating themechanism provided for the development station;

FIGURE 4 is a view of a corona charging electrode according to oneembodiment of the invention;

FIGURE 5 is a plan View of an alternative form of projection slitadvantageously employed under certain circumstances;

FIGURE 6 is a side view, partly in section, of a preferred form of lenscarriage and actuating mechanism;

FIGURE 7 is a transverse view, partly in section, along the lines of 7-7shown in FIGURE 6;

FIGURE 8 is a side view of an alternative embodiment of the inventionshowing a preferred form of uniform lighting by having the light sourceconnected to and movable with the slit-provided carriage; and

FIGURE 9 shows an embodiment of the invention in connection with thereproduction of the visible image from the face of a cathode ray tube.

Referring more particularly to FIGS. 1 and 2, a xerographic machinegenerally designated 10 consists of a cylindrical member 11 providedwith a xerographically sensitive surface. Around the cylinder areassembled the various stages of operation for the xerographic process.These stages include an exposure station 12, a developing station 13,and a regeneration station 14, paper feed station 15, transfer station16, and a cleaning station 17 followed by a charging station 18.Positioned above the exposure station and spaced apart are a movablelens system 1'9 and a xed support 20 for the original or master to becopied, together with a slit projection arrangement and a source oflight 9, for example, sun lamps, operating preferably on the reilectedback o1- opaque system.

At the exposure station, generally designated 12, is a hood or bellowsor other shield 21 adapted to protect the xerographic surface fromextraneous light and having a slit 22 at its lower portion adjacent tothe surface. The upper end of this shield 21 is open to receive anoptical image from a master or original as described hereinafter.Closely adjacent but spaced from the shield and positioned above it is aslotted track 24 on which is mounted a carriage 25 supporting andcarrying a lens 26 which is thereby movable above and across the upperend of the shield 21. Spaced above this track 24 is a second track 2S,likewise bearing a carriage 29, which carriage has a tranverse slit 30extending thereacross. Preferably, for ease of motion, both of thesecarriages may be mounted on balls 27 and wheels 31 respectively or othermeans or mechanism may be employed to cause these carriages to move orslide easily and smoothly along their track. To avoid vibration of thelens while it is moving, it has been found desirable to mount the lens(see FIGS. 6 and 7) in a heavy metallic carriage 25 and to employchannels 32 formed in the heavy metal carriage 25 for the lens and intrack 24, and by positioning for use in the channels four metal balls27, held in place by a suitable bearing cage (not shown). This heavymetal and ball construction can be machined to a high degree ofperfection to avoid the vibration of the lens.

Positioned above the upper track 28 is a fixed support 20 consisting,for example, of a copy board 33 which may consist of a transparent planemember such, for example, as a glass plate or the like, which is adaptedto receive a master or original placed face downward, on its uppersurface, in position for having its image projected through the lens onto the sensitive surface of the cylinder 11, and positioned over thecopy board 33 is a flexible copy cover 23, made, for example, ofplastic, for holding copy flat against the upper surface of the copyboard.

In order to provide for correlated motion of the lens carriage 25 andslit-provided carriage 29 in their travel across the respective tracks24 and 28, whereby an optical image from the original placed facedownwardly on copy board 33 can be projected onto the photosensitivesurface of the cylinder il in proper coordination with the rotation ofthe cylinder, there is provided the following carriage-actuatingmechanism: Partial gear 34 is integrally a part of the cylinder oroptionally is integrally mounted on an axle 35 with which the cylinderrotates. Adjacent to this partial gear is a cam 36 integrally a part ofthe cylinder or optionally integrally mounted on the axle 35. Adjacentto the partial gear 34 is a gear wheel 37 mounted on or connected with afirst or inner pulley wheel 3S and a second or outer pulley wheel 39.The relative sizes of partial gear 34, gear wheel 37, the inner pulleywhee 3S and of pulley wheel 39 are coordinated and related so that thecircumference of pulley wheel 39 rotates at the same speed as thecircumference of cylinder lll, while the inner pulley wheel 3S is ofone-half the diameter of pulley wheel 39, whereby its circumferencemoves at one-half the linear rate of the motion of cylinder il. Camarrangement 36a, fixed to gear 37, cooperates with cam 36 to give to thelens assembly a gradual start. Around the circumference of partial gear34.- are gear teeth eil extending along to a length such that pulley 59is driven through a distance equal to the maximum length of copy whichis to be produced from the original on copy board 33. Flexible tapes 4land 42. are secured to the circumference of pulleys 33 and 39,respectively. Tape il passes over freely movable wheels 44 positioned inline with track 24 and extending therebyond to a carriage returnmechanism which may, for example, be a weight 45 suspended at the freeend of tape di. In a similar mener, tape 42 passes over freely movablewheels i6 in line with track 23 and is secured to a return mechanismwhich likewise may suitably be a weight 47 secured to the free end oftape 4?; after it passes over wheel 46. Tapes 41 and in turn are securedby fasteners 4.18 to carriages 25 and 29, respectively, whereby linearmotion of the tapes draws the carriages along their tracks at acorresponding rate of speed.

From the foregoing, it can be seen that a single rotation of partialgear wheel 34 causes a partial rotation of pulleys 38 and 39 with theconsequent winding up of tapes 41 and 42 across the pulleys, causingcarriages 25 and 29 to be drawn across their tracks, carriage 25 at arate of speed equal to one-half the rate of rspeed of the surface ofcylinder 11 and carriage 29 at a speed equal to the speed of cylinderil. Upon completion of the drive motion, completed by the release ofpartial gear 34 from gear 37, the carriage return mechanisms, that is,weights 45 'and 47, return the carriages to their original positions inpreparation for another cycle of operation. parent, therefore, thatduring the drive phase of the cycle an optical image from the originalplaced on copy board 33 is projected through lens 26, such projectedimage passing through slit '22 on to the surface of cylinder ll inmirror-image relation such that the image received by the movingcylinder surface is a true projected image of the original to be copied.

In the case of slit projection, it is important that uniform lighting beprovided during the projection. The source of light 9, which may be sunlamps, is suitably located to provide for reflected-back or opaqueprojection between the lens and the original to be copied. it isdesirable to illuminate all areas of the slit uniformly during all partsof the cycle of projection. Accordingly, the sun lamps or other sourceof light 9 may be connected with the movable carriage 29 carrying theslit 3) so that movement of the carriage and slit results incorresponding movement of the light, resulting in uniform lighting ofthe slit at all times. Such a system is illustrated in FIG. S. Thecarriage 29 traveling in track 23 is provided with copy board 33 onwhich the original to be copied may be placed face downwardly. Sun lamps9 are afiixed to the carriage by means of bracket 9b positioned belowthe slit 36 to provide for the reflected uniform lighting of the lIt isapg rejection `slit during the transverse movement of the carriage.

The size of the apparatus disclosed may be reduced with the use of awide angle lens. In such case, it may be that a certain amount of unevenlighting of the slit 1s necessary. A form of slit that may beadvantageously employed is illustrated in FIG. 5. Such a slit 381) 1sprovided with greater width at its extremes 39C than at its center 39d.This form of slit may also be profitably employed in connection withslit projection where difficulties due to uneven lighting m-ay beencountered.

lt is to be noted that the apparatus described herein may be used forreproductions of the same size as the original or for larger or smallersizes as may be desired. When one-to-one reproductions are to be made,the lens will be positioned halfway between the photographicallysensitive moving surface and the original to be copied. When smallerreproductions are desired, then the lens is positioned closer to thephotographic surface than to the original. For example, when the lens islocated at onethird the distance from the surface to the original, thena reduction in the reproduction to one-half is accomplished. In theopposite way, larger reproductions may be produced.

In the copying machine herein described, when adjustment of the spacingof the lens between the sensitive surface and the original is made, acorresponding adjustment of the linear distance through which the lenscarriage 25 and the carriage 29 provided with a transverse slit shouldalso be made. For example, when tue lens is positioned one-third thedistance from the plate to the fixed position of the original as when ahalf-sized reproduction is desired, the lens should move one-third ofthe distance that the slit moves through. The rate of speed of the lensto that of the motion of the slit must therefore be adjustedaccordingly. ln the machine described, this adjustment may be effectedby suitable designing of the size of the respective gear wheels 3d and37 or the pulleys 3S and 39. Automatic means controlling the movement ofthe lens and the slit under these different circumstances may beprovided so that simple and expedient means may be used to produce,respectively, oneto-one reproduction, enlargements and reductions usingthe slit exposure system shown. As a general rule, the slit should besmall with respect to the diameter of the drum. It has been found that,in the case of a l5 to 3() inch diameter drum, the slit may be adjustedup to one inch to achieve proper radiation intensity.

Disposed adjacent to the exposure station l2 and directly subsequentthereto in the direction of rotation of cylinder il is the developmentstation i3 comprising essentially a developing hopper Sil adapted toreceive and contain a charge of a developing material for a xerographicprocess. Preferably, the developing hopper has side walls 52 andtapering bottom walls 53 which lead down to a discharge orifice 53. Aclosure member or gate 55 is mounted, for example, pivoteily on asupport S6 so a3 to open and close discharge orifice 54. The motion ofthis gate 55 is controlled by suitable means such, for example, as anelectrically operated solenoid 57 which may cause the gate 55 to bepivoted on its support 56. Preferably, a baftie 59 is adjustably locatedadjacent to the discharge orice 5d and is positioned and adapted tocooperate with gate 55 in closing the developing hopper 5l. When thegate 55 is in its open position, it is close to but free from contactwith the surface of cylinder il. Batlle 59 and gate 55 are disposed andpositioned to direct the flow of developer material from the hoperagainst the surface of cylinder ifi.

Desirably, the developer hopper 5l is disposed and located near theupper portion of the cylinder in such position that the developerlmaterial which is delivered from the hopper falls to the surface of thecylinder at a position where the surface is relatively near to thehorizontal `but at a definite angle from the horizontal. Thus,

for example, it is desirable that the developer material from the hopperfall upon the cylinder where the cylinder surface is at an angle betweenabout and 45 from the horizontal so that the material can cascade orroll across the surface of the cylinder for a substantial distance incontact with the surface.

At the next subsequent position around the cylinder and preferablylocated at or below the axis of the cylinder is a developer catcher 6)which may still be regarded as part of the developing station. Thisdeveloper Catcher may be provided with a catching chute 61 positionedand adapted to catch and receive the development material cascading fromthe hopper across and 4along the surface of the cylinder and adapted toconvey and direct the developer material to a mixing chamber 62.According to one embodiment of the invention, the mixer 62 is in theform of a cylindrical tumbler mounted at an angle of about 20 from thehorizontal and having a plurality of vanes 63 (FIG. l). The mixer ismounted on bearing supports 65 adapted to be rotated by suita-ble drivemechanism (not shown) and feeds into a bucket type return elevatorcomprising a belt 66 carrying buckets 67 around lower and upper wheels69, the whole elevator mechanism being contained within a shield orcasing 70. At its upper end, the bucket elevator feeds into a returnchute 71 which in turn feeds the development material into the developerhopper 51 for a repetition of the cycle. At another station around thecylinder 11, it may be desirable to have a reverse charging orregeneration station at which a charge is applied to the sensitivesurface, the charge being of polarity opposite to that which is appliedfor the initial sensitizing step described hereafter. Thus, optionally,a reverse charging or regeneration station 14 may be positioned nextsubsequent to the developer station in the direction of rotation of thecylinder and prior to the proper feed and transfer stations and 16. Inthe reverse charging station, generally designated as 14 (see FlG. 1),there is provided a suitable charging member such as a corona dischargeelectrode 72 consisting of one or more tine conductive strands forcorona discharge wires 73, control electrodes '75, and preferably aground plate 74 similar to the charging electrode 13d to be describedhereinafter.

Positioned next and `adjacent to the regeneration station is acopy-feeding station provided with suitable sheet-feeding mechanismadapted to feed sheets of paper successively to the cylinder 11 incoordination with the presentation of the developed image at thecopy-feeding station. This sheet-feeding mechanism includes a sheetsource 81 such as a tray for a plurality of sheets 82 of a suitabletransfer material-that is, typically, sheets of paper or the like and apair of feed rollers S3 and 84 adapted to direct the sheet material intocontact with the rotating drum at a speed preferably slightly in excessof the rate of travel of the surface of the drum. One of these rollersS3 is a driven roller operated by a chain of gears 86, S7 and 8S, drivenin turn by a gear 89 integrally connected with the rotating cylinder 11.Preferably, gear S9 is a partial gear whereby the paper feed rollers 83and tid are driven only during the portion of the cycle where it isdesired to feed the sheet material to the surface of the drum. A feedingfinger 91 is driven by a shaft 92, which in turn is operated by arrn 93,pivotally secured to fixed support 94, the arm 93 being energized by afeeding member or cam follower 95, driven by cam 96, whereby the feedingfinger 91 is adapted to feed the top sheet of the stack 82 to the feedrollers S3 and 84 in coordination with the appearance of the developedimage at the paper feed station as may be determined by the cam 96. Inthis manner, the sheet material is introduced between the feed rollersand is thereby brought into contact with the rotating cylinder 11 at thecorrect time and position to register with the developed image.

Preferably, at the exact point of contact between the sheet material andthe rotating drum, a transfer station 16, consisting of a coronadischarge electrode, is positioned to effect transfer of the developedimage from the cylinder surface to the sheet material. The transferelectrode consists essentially of one or more corona discharge wires 97and control electrodes 99 positioned and disposed above a ground plate98 substantially similar to the discharging electrode 18 to be describedhereinafter. The sheet-feeding and transfer mechanism are similar to thetype disclosed in Mayo et al. Patent 2,684,902, filed November 23, 1951.

Immediately subsequent to the transfer station 16 are positioned striplingers y1111 operated by arm lill7 in turn energized by cam member orfollower 103 driven by a second cam 104 integrally mounted on orconnected with the rotating cylinder 11. These strip or pick-off fingersare adapted to Ibe 4brought into contact with the surface of thecylinder 11 slightly in advance of the sheet material and to strip thesheet material from the cylinder surface, directing the free 4sheetmaterial into a fixing mechanism generally designated 105 and furtherdened in a copending application Serial No. 232,- 152, tiled June 18,1951, now Patent No. 2,701,765. The fixing apparatus disclosed in FIG. 2consists essentially of a heated rotating drum 111 and a coronadischarge electrode 112 or the like, spaced closely adjacent thereto andadapted to receive the sheet material therebetween, whereby the sheetmaterial is secured by electrostatic adhesion to the surface of theheated drum, and the developed and transferred image is fixed thereon byconducting heating from the surface of the drum through the sheettransfer material. Cylinder 111 preferably is contained within a housing113 and is driven by motor 113' operating through drive wheel 114 andbelt I11S to drive the heating cylinder at a rate which optionally maybe the same as that of the rotation of cylinder 11. Sliding pick-offfingers 116 serve to pick the sheet material from the surface of heateddrum 111 and direct it into a tray 117 wherein the completed xerographicprint is collected and stored.

Positioned next subsequent to the transfer and pick-up station is acleaning station generally designated 17, at which is disposedcylindrical brush 121 rotatively mounted, for example, on axle 122 andadapted to be driven by a motor 123 operating through belt 12d. Theentire cleaning section is mounted within a housing 125 with asub-housing or hood 126 surrounding the cylindrical lbrush as disclosedand illustrated in FiG. 2. The cylindrical brush may consist, forexample, of rabbit fur secured on the surface of a solid or structuralcylinder 127 and be rotated in a direction opposite to the direction ofrotation of the cylinder surface at the point of contact, so that therelative motion between the brush surface and the cylinder surface isthe sum of the two separate speeds of motion. A filter member 12S may bepositioned in one wall of the hood, preferably the lower wall thereof,to permit passage of air therethrough but at the same time to collectdust or electroscopic particles removed from the surface of the cylinderby the brush. In the mechanism as illustrated in FIG. 2, the brushfibers, due to the high centrifugal force caused by the rotating motion,extend outwardly until they reach in contact the cylinder surface, whenthey are somewhat depressed. Immediately upon release, the brush fibersextend outwardly again from the surface, thus causing a vane-like actionwhich causes a flow of air into the hood area at the space between thehood and the cylinder and out through filter 12S. In this manner, aconstant ilow of air serves to free the brush libers from electroscopicparticles picked up lby the cleaning action and thus to maintain absenceof dust in the surrounding atmosphere. lf desired, this air flow `actionmay be supplemented through the use of a supplemental vacuum flow froman air blower or the like (not shown).

Next subsequent in the direction of rotation of cylinder lll isoptionally positioned a light discharge source such, for example, as aneon light 1.3i placed directly over the surface of the cylinder il andadapted to ood the entire surface of the cylinder with light prior toits entering into the next subsequent process stage of charging, thusassuring at this point complete photoconductive dissipation of anyresidual electric charge from the photoconductive sensitive surface ofthe cylinder.

The nal stage through which the rotating cylinder surface passes, whichstage may be considered as an initial stage of this or a subsequentcycle, is a charging station 1S wherein the cylinder surface is adaptedto pass under a corona discharge electrode, generally designated as inFlG. 2, consisting of one or more tine conductive strands or coronadischarge wires 132 optionally with a ground plate 133 at leastpartially sur-rounding the wires. Control electrodes 134 are providedbetween the discharge wires 3l32 and the surface of cylinder 1l wherebythere occurs a flow of gaseous ions from the wires to the cylindersurface. This corona discharge is of the type described and claimed incopending application Serial No. 221,582, now Patent No. 2,778,946.

Cylinder or drum lll around which are stationed the various stages ofthe photographic process provides a cylindrical support surface of anelectrically conductive material such, for example, as a metal surfaceor the like, on which is placed a photoconductive insulating layer such,for example, as a layer or coating of vitreous selenium or otherphotoconductive insulating material. Suitable for this purpose arevarious photoconductive insulating compositions characterized by anextremely high specific resistivity in the absence of illumination,which resisitivity drops at least several orders of magnitude uponexposure to bright light. Suitable material, in addition to seleniumcompositions, include, for example, anthracene, sulphur,sulphur-selenium mixtures and the like, as well as other photoactivematerial characterized 'by high insulation in the dark and byphoto-initiated conductivity such, for example, as photoactivation ofelectrons in the molecular structure to a conductivity band or by othertransitory or permanent change in conductivity upon exposure to light.it is to be understood that the cylinder l1 may be a cylinder surfacehaving a photoconductive insulator directly on its surface or may, ifdesired, have a support member adapted to receive and support incylindrical conguration one or more separate xerographic membersconsisting of a conductive backing and a photoconductive layer thereon.Then, if desired, the drum or light member may be directly coated with avitreous selenium composition or, alternatively, a rigid or llexiblexerographic member may be suitably secured to the surface of acylindrical support member.

In the device and apparatus disclosed in the drawings herein, thevarious mechanisms connected with the stations of exposure, paperfeeding, paper pick olf, and the lil-ie, are controlled by a singleunit, gears and partial gears, and by single unit cams, and thereforeare adapted to cooperate with a cylinder or drum containing a singlexerographic member or a single xerographic station at its surface. It isto be understood, however, that a plurality of such members or stationsaround the cylinder may be employed and that a plurality of partialgears, cam members, and the like may be used in cooperation therewith,whereby two or more separate xerographic cycles may be accomplished in asingle revolution of the cylinder or drum ll. Such an arrangement may bedesirable under certain circumstances and be adapted for a plurality ofcycles in a single cylinder revolution.

In the disclosure of the preferred form of embodiment of the invention,a cylinder or drum has been employed to provide a movable photosensitivesurface. Such a movable surface may be secured in other ways, such as amovable plate or belt and the invention is also applicable thereto.

The mechanism disclosed herein is suitable for the reproduction of oneor more copies of an original placed on the copy board By suitablemeans, such as handpositioning or by mechanical means, the desiredoriginal material is placed on the copy board. The cylinder is thenenergized and exposure takes place with the carriages 25 and 29 passingacross the surface of the copy in synchronized motion and correlatedspeed according to the rotation of cylinder lli. The exposed portion ofthe surface of the cylinder then passes into the developing stationwherein a suitable developer material is cascaded across the surface andis collected by the developer catcher and returned to the developerproper. The exposed and developed portion of the surface of the cylinderlll then passes to the paper-feeding station and the transfer sta.- tionwhere it receives a sheet of transfer copy material and passes under acorona discharge whereby the developed image is transferred to the paperor other transfer member` The cylinder, with the adhering transfersheet, then passes to the pick-up iingers Mil where the sheet isstripped from the cylinder surface and enters the fixing chamber whereinthe transferred image is fixed to the transfer sheet by heat fusing orthe like. The cylinder surface then passes to the cleaning station whereany residual powder is removed by brush 121 and then after coming underdischarging light lill the surface passes to the charging electrode l@where an electrostatic charge is deposited on the surface of the drumand the drum is thus sensitized or re-sensitized and prepared for thesucceeding exposure and development cycle. At this stage, if more thanone copy is desired, the cycle is repeated until sufficient copies areobtained, whereupon a different original is placed on the copy board andthe cycle then repeated as desired.

According to the presently preferred procedure, the developmentcomposition employed includes a two-component developer consisting ofgrossly larger carrier particles and fine electroscopic powderparticles, coated on the surface thereof such, for example, as describedin Patent No. 2,618,55l. As the process continues through the repetitivecycles, the quantity of electroscopic powder material in the combinationdeveloper may become depleted and it accordingly is desirable toreplenish the developer composition with additional electroscopicpowder, either continuously or from time to time. The replenishment ofthe developer composition may be achieved by adding to the developermixture in the tumbler 62 or immediately prior thereto a smalladditional quantity of the electroscopic powder material. The additionof this small quantity of developer powder may be accomplished manuallyor, if desired, by automatic means by a replenisher opening 62a as shownin Fl G. l. The developer composition with the replenishing powder ismixed in tumbler 62, whereupon uniform intermixing is achieved and thecombination developer is then re-cycled into the developer hopper forre-use through one or more succeeding xerographic cycles.

According to a further embodiment of the invention, the mechanism asherein described is adapted for the reproduction of an optical imageformed on the face of a cathode ray tube or like source of conversion ofenergy. A suitable embodiment of this mechanism may be that disclosed inconnection with FIGS. l and 2 wherein the face of the cathode tube issubstituted for the original Ztl to be copied as shown in those figuresor an embodiment such as shown in FIG. 9 wherein the lens 26 is kept inconstant position over the exposure section l2 of the cylinder ll and isnot caused to travel back and forth across the exposing station. ln thismodification. a cathode tube 99 with its face o is held above the shield2l of the exposure section which in turn is located above the rotatablecylinder ll. The photosensitive surface of the cylinder ll rotatesthrough the exposure station 12 and then through correspondingdeveloping station, paper feed station, transfer station, cleaningstation, and charging station, all as disclosed in FIGS. 1 and 2. Anelectrical image is fed to the cathode ray tube according toconventional electronic circuits, to yield an image on or moving acrossthe face of the tube in coordination with the rotation of the cylinder.This optical image is projected and focused on to theelectrophotographically sensitive cylinder surface to form thereon anelectrostatic latent image which in turn is developed and transferred tocopy sheet material or the like, all as previously described and shownin connection with FIGS. l and 2. When a cathode ray tube or like sourceof an optical image is employed in conjunction with the vitreousselenium type of the Xerographic surface, it is preferable that the faceof the cathode ray tube contain a phosphor, preferably one which isrelatively high in spectral sensitivity in the blue-green range, thispresently being the spectral range of greater sensitivity for thevitreous selenium xerographic surface. The sensitivity of thexerographic member or surface is such, however, that it performssatisfactorily with substantially all conventional phosphor lightemitters.

While this invention has been described in preferred form, it is to beunderstood that modifications thereof may be made without departing fromthe ambit of the invention as dened by the appended claims.

What is claimed is:

l. An apparatus for projecting a light image on a moving surfacecomprising a copy holder for supporting copy substantially in a plane,illuminating means to illuminate copy supported by the copy holder; saidilluminating means including a slotted light shield for exposing atransverse section of the copy holder, a light source for illuminatingsuch exposed section, and means for supporting the light shield andlight source for movement to traverse the surface of the copy holder; amovable light receiving surface having a path of movement arranged toreceive light refiections from the copy holder, means for moving saidsurface at a predetermined speed, a light shield interposed between thelight receiving surface and the copy holder, a slot aperture in thelight shield extending transversely to the path of movement of the lightreceiving surface, a lens element for focusing light reflections fromthe copy holder through the slot aperture, a lens carriage forsupporting the lens element, said carriage being movable in a path totraverse the plane of the copy holder, means for moving the lenscarriage and the light source supporting means at differingpredetermined speeds relative to the speed of the light receivingsurface, and means to restore the lens carriage and the light sourcesupporting means to their respective traverse starting positions.

2. An apparatus for projecting a light image onto a rotating xerographicdrum comprising a copy holder for supporting copy substantially in aplane, means to illuminate copy supported by the copy holder; saidilluminating means including a slotted light shield for exposing atransverse section of the copy holder, a light source for illuminatingsuch exposed section, and means for supporting the light shield andlight source for movement to traverse the surface of the copy holder; axerographic drum mounted for rotation about an axis parallel to theplane of the copy holder and arranged to receive light reflections fromthe copy holder, means for rotating said Xerographic drum at apredetermined speed, a light shield interposed between the xerographicdrum surface and the copy holder, a slot aperture in the light shieldextending transversely to the path of movement of the xerographic drumsurface, a lens element for focusing light reflections from the copyholder through the slot aperture, a lens carriage for supporting thelens element, said carriage being movable in a path to traverse theplane of the copy holder, means for moving the lens carriage and thelight source supporting means at differing predetermined speeds relativeto the speed of the xerographic drum surface, and means to restore thelens carriage and the light source sup- 10 porting means to theirrespective traverse starting positions.

3. An apparatus for projecting a light image on a moving surfaceincluding a fixed copy support means for supporting copy substantiallyin a plane, movable illuminating means operatively positioned totraverse and illuminate the copy supported by said fixed copy supportmeans, a movable light receiving surface operatively positioned toreceive light reflections from the copy supported by said fixed copysupport means, a xed light shield operatively interposed between saidlight receiving surface and said fixed copy support means, a slotaperture in said light shield extending transversely to the path ofmovement of said light receiving surface, a movable lens carriageoperatively positioned for movement in a path to traverse the plane ofsaid fixed copy support means, a lens element connected to said movablelens carriage for focusing light reflections from the copy supported bysaid fixed copy support means through said slot aperture, and meansoperatively connected to said movable illuminating means, said lightreceiving surface and said movable lens carriage to move said movableilluminating means, said light receiving surface and said movable lenscarriage at predetermined speeds relative to each other.

4. The apparatus of claim 3 wherein said movable illuminating meansincludes a slotted light shield for exposing a transverse section of thecopy supported by said fixed copy support means, a light source, andmeans for supporting said slotted light shield and said light source formovement to traverse the surface of the copy supported by said xed copysupport means.

5. An apparatus for projecting a light image on a moving surfaceincluding a copy support means for supporting copy substantially in aplane, movable illuminating means operatively positioned forilluminating successive portions of the copy positioned in said copysupport means in timed relation to the movement of a lens, a movablelight receiving surface operatively positioned to receive lightreflections from the copy supported by said copy support means, a fixedlight shield operatively interposed between said light receiving surfaceand said copy support means, a slot aperture in said light shieldextending transversely to the path of movement of said light receivingsurface, a movable lens means operatively positioned for movement in apath to permit said movable lens means to receive light reflections fromthe copy supported by said copy support means and means operativelyconnected to said movable illuminating means, said movable lightreceiving surface and said movable lens means to move said movableilluminating means, said movable light receiving surface and saidmovable lens means at predetermined speeds relative to each other.

6. The apparatus of claim 5 wherein said movable illuminating meansincludes a slotted light shield for exposing a transverse section of thecopy supported by said copy support means, a light source, and means forsupporting said slotted light shield and said light source for movementto traverse the surface of the copy supported by said copy supportmeans, and said movable rlens means includes a lens mounted on a movablecarriage.

7. An apparatus for projecting a light image onto a rotating xerographicdrum comprising a copy holder for supporting copy substantially in aplane, illuminating means to illuminate copy supported by the copyholder; said illuminating means including a slotted light shield forexposing a transverse section of the copy holder, a ylight source forilluminating such exposed section, and means `for supporting the lightshield and light source for movement to traverse the surface of the copyholder; a xerographic drum mounted for rotation about an axis parallelto the plane of the copy holder and arranged to receive lightreflections from the copy holder, means for rotating said Xerographicdrum at a predetermined speed, a light shield interposed between thexerographic drum surface and the copy holder, a slot aperture in thelight shield extending transversely to the path of movement of thexerographic drum surface, a lens element for focusing light rellectionsfrom the copy holder through the slot aperture, -a lens carriage forsupporting the lens element, said carriage ybeing movable in a path totraverse the plane of the copy holder, and means `for moving the lenscarriage and the light source supporting means at differentpredetermined speeds relative to the speed of the xero-graphic drumsurface.

8. An apparatus for projecting a light image onto a rotating xerographicdrum comprising a copy holder for supporting copy substantially in aplane, means to illuminate copy supported by the copy holder; saidilluminating means including a slotted light shield for exposing atransverse section of the copy holder, a light source for illuminatingsuch exposed section, and means for supporting the light shield formovement to traverse the surface of the copy holder; a xerographic drummounted for rotation about an axis parallel to the plane of the copyholder and arranged to receive light reections from the copy holder,means for rotating said xerographic drum at a predetermined speed, alight shield interposed between the xerographic drum surface and thecopy holder, a slot aperture in the light shield extending transverselyto the path of movement of the xerographic drum surface, a lens elementfor focusing light rellections from the copy holder through the slotaperture, a lens carriage for supporting the lens element, said carriagebeing movable in a path to traverse the plane of the copy holder, andmeans for moving the lens carriage and the light shield supporting meansat differing prede-y termined speeds relative to the speed of thexerographic drum surface.

9. An appaaratus for projecting a light image on a moving surfacecomprising a copy holder for supporting copy substantially in a plane,means to illuminate copy supported by the copy holder; said illuminatingmeans including a slotted light shield for exposing a transverse sectionof the copy holder, a light source for illuminating such exposedsection, and means for supporting the light shield and light source formovement to traverse the surface of the copy holder; a movable lightreceiving surface having a path of movement arranged to receive lightreflections from the copy holder, means for moving said surface at apredetermined speed, a light shield interposed between the lightreceiving surface and the copy holder, a slot aperture in the lightshield extending transversely to the path of movement of the lightreceiving surface, a lens element for 4focusing light reflections fromthe copy holder through the slot aperture, a lens carriage forsupporting the lens element, said carriage being movable in a path totraverse the plane of the copy holder, and means yfor moving the lenscarriage and the light source supporting means at diiferingpredetermined speeds relative to the speed of the light receivingsurface.

l0. An apparatus for projecting a light image onto a moving surfacecomprising a stationary copy holder for supporting copy substantially ina plane, means to illuminate copy supported by the copy holder, amovable light receiving surface having a path of movement arranged toreceive light rellections from the copy holder, means for moving saidsurface at a predetermined speed, a light shield interposed between thelight receiving surface and the copy holder, said light shield having aslot aperture arranged adjacent the light receiving surface andextending transversely to the path of movement thereof, a movable lenselement mounted between the copy holder and the slot aperture, said lenselement being movable in a path to scan the plane of the copy holder,and means for moving the lens element at a rate proportional to that ofthe light receiving surface whereby a ilowing image of copy is projectedonto said movable light receiving surface.

l1. An apparatus for projecting a light image onto a moving surfacecomprising a stationary copy holder for supporting copy substantially ina plane, means to illuminate copy supported by the copy holder, a movinglight receiving surface having a path of movement arranged to receivelight reflections from the copy holder, a light shield interposed`between the light receiving surface and the copy holder, said lightshield having a slot aperture arranged adjacent the light receivingsurface and extending transversely to the path of movement thereof, alens element for focusing light reflections from the copy holder throughthe slot aperture onto said moving light receiving surface, and a lenscarriage for supporting the lens element, said lens carriage beingmovable in a path whereby said lens element scans the plane of the copyholder and means for moving the lens carriage at a predetermined speedrelative to said light receiving surface.

l2. An apparatus for projecting a light image onto a moving surfacecomprising a stationary copy holder for supporting copy substantially ina plane, means to illuminate copy supported by the copy holder, amovable light receiving surface having a path of movement arranged toreceive light rellections from the copy holder, means for moving saidlight receiving surface at a predetermined speed, a light shieldinterposed between the light receiving surface and the copy holder, aslot aperture in the light shield arranged adjacent the light receivingsurface and extending transversely to the path of movement of the lightreceiving surface, a lens element for focusing light rellections fromthe copy holder through the slot aperture onto said moving lightreceiving surface, a lens carriage lfor supporting the lens element,said lens carriage being movable in a path to traverse the plane of thecopy holder whereby copy supported by the copy holder is scanned by saidlens element, and means for moving the lens carriage at a predeterminedspeed relative to the speed o-f the light receiving surface.

13. An apparatus for projecting a light image onto a moving surfacecomprising a stationary copy holder for supporting copy substantially ina plane, means to illuminate copy supported by the copy holder, amovable light receiving surface having a path of movement arranged toreceive light rellections from the copy holder, means `for moving saidlight receiving surface at a predetermined speed, a light shieldinterposed between the Ilight receiving surface and the copy holder, aslot aperture in the light shield arranged adjacent the light receivingsurface and extending transversely to the path of movement of thelight-receiving surface, a lens element for focusing light rellectionsfrom the copy holder through the slot aperture onto the light receivingsurface, a lens carriage 'for supporting the lens element, said -lenscarriage being movable in a path to traverse the plane of the copyholder from a start-of-scan position to an endof-scan position wherebysaid lens element scans copy supported thereon, means for moving thelens carriage at a predetermined speed relative to the speed of thelight-receiving surface from said start-of-scan position to saidend-of-scan position, and means to restore the lens carriage to itsstart-of-scan position.

14. An apparatus for projecting a light image on a moving surfaceincluding a copy holder for supporting copy substantially in a plane,means to illuminate copy supported by said copy holder; saidilluminating means including a light source, and means for supportingsaid light source for movement to traverse the surface of the copyholder; a movable light-receiving surface having a path of movementarranged to receive light reflections from the copy holder, means formoving said lightreceiving surface at a predetermined speed, a lightshield interposed between said light-receiving surface and said copyholder, a slot aperture in said light shield extending transversely tothe path of movement of said lightreceiving surface, a lens element fordirecting light rellections from said copy holder through said slotaperture and onto said light-receiving surface, a lens carriage forsupporting said lens element, said lens carriage being movable in a pathto traverse the plane of the copy holder, and means for moving said lenscarriage and 13 said means for supporting said light source at differingpredetermined speeds relative to the speed of said lightreceivingsurf-ace.

15. An apparatus -for projecting a light image on a moving surfaceincluding a copy holder for supporting copy substantially in a plane,means to illuminate a copy supported by said 4copy holder, said meansincluding a light source, and a carriage for supporting said lightsource for movement to traverse the surface of said copy holder, amovable light-receiving surface having a path of movement arranged toreceive light reections from said copy holder, means for moving saidsurface at a predetermined speed, a light shield interposed between saidlight-receiving `surface and said copy holder, a slot aperture in saidlight shield extending transversely to thc path of movement of saidlight-receiving surface, a lens element Ifor directing light4reilections yfrom said copy holder through said slot aperture and ontosaid lightreceiving surface, a lens carriage `for supporting said lenselement, said lens carriage being movable in a path to traverse theplane of said copy holder', means for moving said lens carriage and saidcarriage for supporting said light source at differing predeterminedspeeds relative to the speed of said light-receiving surface, and meansto restore said lens carriage and said carriage for said light source totheir respective traverse starting positions.

16. A copying apparatus including a copy holder for supporting copysubstantially in a plane, illuminating means to illuminate a copysupported by said copy holder, a xerographic drum mounted for rotationabout an axis, a light shield positioned adjacent the surface of saidxerographic drum, a slot aperture in said light shield that extendsnormal to the path of movement of the surface of said xerographic drum,said slot aperture being arranged adjacent the surface of thexerographic drum, a lens carriage, a lens element mounted on said lenscarriage, said lens carriage being mounted for movement to transportsaid lens element in a path to scan copy on said copy holder and toproject a owing image of copy through said slot aperture in said lightshield onto said xerographic drum, and means connected to saidxerographic drum and to said lens carriage to move said lens carriage ata predetermined speed relative to the speed of the surface of saidxerographic drum as it is rotated by said means.

17. An apparatus for projecting a Ilight image from a stationary copyonto a xerographic drum including a copy holder for supporting a copysubstantially in a plane, illuminating means to illuminate a copysupported by said copy holder, xerographic drum mounted for rotationabout an axis, a light shield interposed in the light path between saidcopy holder and said xerographic drum, a slot aperture in said lightshield extending transversely to the path of movement of the surface ofsaid xerographic drum, a lens element for focusing light reections froma copy on said copy holder through said slot aperture of said lightshield and onto said xerographic drum, a lens carriage `for supportingsaid lens element, said lens carriage being mounted for movement in a-path to traverse the plane of said copy holder, and means connected tosaid xerographic drum and said lens carriage to rotate said Xerographicdrum and to periodically move said lens carriage at a predeterminedspeed relative to the surface speed of said xerographic drum from astarting position to a drive release position, and means to restore saidlens carriage to its traverse starting position.

18. An apparatus for projecting a radiation image from a stationaryoriginal onto a photosensitive member including a copy holder forsupporting an original substantially in a plane, illuminating means forilluminating an original supported by said copy holder, a cylindricalmember adapted to support a photosensitive member mounted for rotationabout an axis, means for imparting rotation to said cylindrical member,a light shield interposed in the light path between said copy holder andsaid cylindrical member, a slot aperture in said light shield extendingtransversely to the path of movement of the surface of said cylindricalmember, a lens element for focusing radiation reflections from anoriginal on said copy holder through said slot aperture of said lightshield onto said cylindrical member, a lens carriage for supporting saidlens element, said lens carriage being mounted for movement in a path totraverse the plane of Said copy holder, a drive means associated inaxial alignment with said cylindrical member and connected for rotationtherewith, a driven means mounted adjacent said drive means and adaptedto be coupled to said drive means to provide coincident rotation thereofafter said drive means has rotated a lirst predetermined distance andadapted to be uncoupled from said drive means kafter an additionalpredetermined rotation, a flexible member adapted to be driven by saiddrive means and having a portion thereof coupled to said lens carriage,said exible member being thereby adapted to impart linear motion to saidlens carriage and to synchronize the linear speed of said lens carriagewith the peripheral speed of said cylindrical member.

References Cited-in the le of this patent UNITED STATES PATENTS2,123,151 Petit et al. July 5, 1938 2,153,186 Henderson Apr. 4, 19392,478,555 Yule Aug. 9, 1949 2,487,671 Pratt et al Nov. 8, 1949 2,606,478Pratt et al Aug. l2, 1952 2,807,190 Oldenboom Sept. 24, 1957 -2,830,491Domeshek Apr. 15, 1958 2,859,673 Hix et al Nov. 11, 1958 FOREIGN PATENTS551,455 Great Britain Feb. 23, 1942

